Osteochondrosis in horses: An overview of genetic and other factors.
Authors: Martinez-Saez, Marín-García, Llobat
Journal: Equine veterinary journal
Summary
# Editorial Summary: Osteochondrosis in Horses—Genetic and Environmental Contributors Osteochondrosis (OC) and its severe form, osteochondrosis dissecans (OCD), represent a significant developmental orthopaedic challenge in sport horses, stemming from disrupted endochondral ossification during growth. Martinez-Saez and colleagues reviewed the multifactorial aetiology of OCD, examining both genetic and non-genetic contributors including rapid growth rate, nutritional imbalances, trauma, conformation, and biomechanical factors. The dramatic variation in OCD prevalence across breeds—ranging from 13% in Swedish Warmbloods to 53% in Lusitanos—underscores the critical role of genetics; research has identified five functional gene clusters controlling cartilage development and regeneration, with specific variants in collagen genes (COL3A1, COL5A1, COL5A2, COL24A1, COL27A1), laminin (LAMB1), cell signalling pathways (PTH, PTH receptors, IHH), and matrix metalloproteinases linked to disease occurrence and severity across different breeds. For equine professionals managing young performance horses, this review highlights that whilst genetic predisposition cannot be modified, targeted intervention on manageable factors—controlled growth rates, appropriate nutrition, training load management, and early recognition of conformation-related risk factors—remains essential to minimising clinical expression of OCD in genetically susceptible individuals.
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Practical Takeaways
- •Breed selection and informed breeding decisions are critical; understanding breed-specific OCD prevalence (13–53%) can guide breeding programs and client counselling
- •Management of modifiable risk factors—particularly controlled growth rates, balanced nutrition, avoiding excessive trauma, and monitoring biomechanical stress—remains essential even in genetically susceptible animals
- •Early detection and intervention are important given the variable clinical presentation ranging from minimal signs to severe joint effusion and lameness, requiring systematic joint assessment in young sport horses
Key Findings
- •OCD prevalence varies significantly by breed, ranging from 13% in Swedish Warmblood to 53% in Lusitano horses, indicating strong genetic influence
- •Five clusters of genes regulate OCD susceptibility through collagen metabolism, laminin structure, cell signalling, matrix turnover, and transcriptional regulation
- •Genetic modifications in COL3A1, COL5A1, COL5A2, COL24A1, COL27A1, LAMB1, PTH, IHH, and matrix metalloproteinase genes are associated with OCD occurrence and severity across different equine breeds
- •OCD aetiology is multifactorial, combining genetic predisposition with non-genetic factors including rapid growth, nutrition, trauma, anatomical conformation, and biomechanics